Abstract: Objective: To explore the role and mechanism of ferroptosis in renal fibrosis through an adenine-induced rat model of CKD combined with in vitro experiments.
Methodology: 5~6-week-old male SPF-grade SD male rats (190-230 g) were randomly divided into Control group (n=15) and CKD group (n=18), and the CKD model was constructed by adenine gavage. At the end of the 2nd, 4th and 6th weekends, 5 rats were randomly selected from each group to be executed, and iron content, malondialdehyde (MDA) content and glutathione (GSH) content were detected. RT-PCR and immunohistochemistry were used to detect the expression of renal ferroptosis and fibrosis-associated factors. In vitro experiments, ferroptosis was induced in human renal tubular epithelial cells (HK-2) by ferroptosis inducer (RSL3) and inhibited by ferroptosis inhibitor (Ferrostatin-1, Fer-1). Cell viability, ferroptosis-related markers, and fibrosis-associated factors were measured after intervention.
Results: The CKD group showed increased iron content, MDA content, and decreased GSH levels. The expression levels of α-smooth muscle actin (α-SMA) and alpha 1 type I collagen (COL1A1) increased, transferrin receptor 1 (TFR-1) and ferroportin (FPN) initially increased and then decreased; ferritin heavy chain (FTH) and 4-hydroxynonenal (4-HNE) levels increased; and GPX4 expression decreased. The above changes showed dynamic progression over time. GPX4 expression level was negatively correlated with α-SMA and COL1A1 levels. RSL3-treated HK-2 cells exhibited reduced viability, increased reactive oxygen species (ROS), decreased GSH content and GPX4 expression, and upregulated α-SMA and COL1A1. The above changes could be reversed by Fer-1.
Conclusion: Ferroptosis was involved in the fibrotic process of adenine-induced CKD rats and contributes to the progression of fibrosis, which may be related to ferroptosis-stimulated transdifferentiation of renal tubular epithelial cells.

Key words: font-family:Inter, -apple-system, BlinkMacSystemFont, ", font-size:16px, background-color:#F9FAFB, ">chronic kidney disease, renal fibrosis, ferroptosis